SIG Sauer M400 Tread 5.56 AR Pistol - ROMEO-MSR - 11.5"

Manufactured by Sig Sauer
Manufactured by Sig Sauer
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NOTE: Limit 1 per household. Quantities exceeding 1 will not allow checkout.

Items that are regulated by the ATF have restrictions and requirements: 
•Your entire order will ship only to a Federal Firearm License holder.
•Current processing time is approximately 14 to 16 days.
•Please contact your local FFL prior to placing your order to ensure they are still accepting transfers. Due to Covid-19 many are no longer open
•A copy of your order/invoice as well as the current FFL license for your local dealer must be emailed to



The SIG Sauer M400 Tread 5.56 AR Pistol is ready for the range straight out of the box with a 30 round Magpul PMAG and SIG ROMEO-MSR red dot sight already mounted with an absolute co-witness lightweight mount. It features an 11.5” barrel with a 1:7 twist rate and an adjustable gas block. The carbon steel barrel features a black Nitride finish and an A2 flash hider with a lightweight M-LOK free float handguard. The lower receiver features ambidextrous controls, an ergonomic pistol grip, and a single stage Mil-Spec trigger. Attached to the carbine length buffer tube is a stabilizing brace for better accuracy and handling. The SIG M400 Tread Pistol is a compact firearm that is a great addition to any collection.

  • 11.5” barrel chambered in 5.56
  • Carbon steel with black Nitride finish
  • Adjustable gas block
  • Lower receiver with integral ambidextrous controls
  • Stabilizing arm brace
  • Includes ROMEO-MSR red dot sight
  • Includes Magpul 30 round PMAG

Sig Sauer is a world-renowned firearms manufacturer with a rich history of innovation and design leadership. No other firearms manufacturer is so highly regarded and so universally respected for the quality, reliability, and safety of its products. Since 1864 they have expanded their product line to include suppressors, optics, ammo, and airguns to provide customers with a greater range of firearms and equipment.
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Barrel CoatingSalt Bath Nitride
Barrel Length11.5
BrandSig Sauer
Caliber Gauge5.56 NATO
Frame SizeAR Pistol
Handguard11 in M-LOK Rail
Muzzle DeviceA2 Flash Hider
Thread Pattern1/2 X 28
Twist Rate1:7
Weight6 lbs.

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